Superkirby Posted September 25, 2013 Share Posted September 25, 2013 And if you want to help me push a Pathfinder off, that would be great as well. Ok, so it's not quite that bad yet, but I feel like I'm running out of patience for this thing. I've been chasing the problem that's causing the "Fuel Injection Circuit" code since shortly after I got this thing in May. I've narrowed it down to cylinder 2. I've changed the fuel injector and the injector connector. I've also changed the TPS, cleaned the MAF, and taken apart and cleaned all the electrical connectors. The only thing that has helped some is taking the connectors apart. Put them back together and it runs great for 2 to 50 miles. If it's not the injector connector, then it would leave me to believe that somewhere the problem is with the wiring in the fuel injector harness. Would that be correct? Working on that assumption, I've been looking all over trying to find that harness. It's possible I could rewire the harness, but wiring scares me and I don't have the luxury of the vehicle being out of commission for more than a day or two. So yeah, trying to find a new harness. I can't find one anywhere. I called a couple of junkyards somewhat close to me and they don't have anything. Don't know where else to look. If someone can help I would appreciate it greatly. You can tell me I'm barking up the wrong tree. You can tell me where to get the harness. I just need some help. Vince Link to comment Share on other sites More sharing options...
Tungsten Posted September 25, 2013 Share Posted September 25, 2013 How about the wiring going to the MAF sensor connector? In most cases the wiring is the issue and not the sensor itself. The rumor is that people don't remove the connector when they change the air filter so it ends up getting broken. Link to comment Share on other sites More sharing options...
Superkirby Posted September 25, 2013 Author Share Posted September 25, 2013 I removed the MAF and cleaned it and it didn't seem to make a difference in anything. It looks to be in acceptable condition as does the wiring to it. When I first narrowed it down to the #2 cylinder, I found I could disconnect all the injector connectors one at a time and #2 was the only one that didn't change how it ran. Changed the injector first. Still the exact same. Changed the connector and again, still the same. This injector has a white/red wire running to it and a yellow wire. I believe the W/R wire is common to all injectors and the yellow is #2 specific. After I was done changing the connector and nothing improved, I was trying to remember what briefly made it better in the past, which was taking apart and cleaning the plugs up above the passenger valve cover. So I moved to those. The yellow wire runs into the lower connector. Pulled them both apart to inspect for dirt and damage. Didn't see anything. Looked at the back of the connector to check for wire damage to the yellow wire. None that I could see. Put them back together. Decided just for kicks to start it up. Sure enough it started up, the CEL went off right away and all was better. Idle is smooth and consistet, blip the gas and it quickly responded, etc. Basically it ran like a v6 should when running on all 6 cylinders instead of 5. Through all this I've concluded my issue about has to be either the connector or the yellow wire. But which one and how do you tell? Better yet, how do you fix it? Link to comment Share on other sites More sharing options...
Vividkid Posted September 25, 2013 Share Posted September 25, 2013 Did you check continuity from the PCM to the injector? If so and it shows good continuity you need to do a voltage drop on the wires in question. You need a factory wiring diagram to start off with. Next disconnect the suspect connector/circuit, in your case the injector. Disconnect the harness from the computer. I like to use a conventional test light but a rigged up automotive light bulb works great. Now you need a some current to run though the wire. I prefer a 12v car battery, but a 9v battery like from an old garage door opener works just as well. You need to connect the battery to the circuit with the test light in series. **Make sure you are on the correct wires and the component and ECU are unplugged or you could introduce voltage to where it's not suppose to go!** If the bulb or light is dim then you know there is an issue in the specific wire either corrosion, or pinched wire that will give you good continuity but cause a voltage drop and not let enough current flow through the wire. You can also use a DVOM if you want to get super technical (Youtube Voltage Drop, there's some great videos). Hope this helps. This technique has saved me countless hours of guessing by isolating a bad wire. Link to comment Share on other sites More sharing options...
Superkirby Posted September 26, 2013 Author Share Posted September 26, 2013 First off, Vividkid - your Pathy in your picture is awesome. I want that one. But anyway, I found a wiring harness at a junkyard. Well, specifically, my dad found it out in WY at a junk yard. But for $40 plus shipping it should hopefully take care of my problem. I hope. I plan to swap the harnesses and then I'll try to pinpoint the problem and replace the wire so I have a spare. Just in case. So that's where it's at. I'll hopefully have it and get it swapped out in about a week. Thanks for the help I just might win. Link to comment Share on other sites More sharing options...
Rebelord Posted September 28, 2013 Share Posted September 28, 2013 Sounds like a plan. Plus, should make it easier to trace and replace bad wires as needed since you'll have some type of guide of what it follows. Link to comment Share on other sites More sharing options...
Kyle94 Posted September 28, 2013 Share Posted September 28, 2013 I wish I knew this when I had my '94... It did the same thing on #2 injector... Changed the I jector nothing. Never got around to the wires... Link to comment Share on other sites More sharing options...
RF600 Posted September 28, 2013 Share Posted September 28, 2013 I don't know what driveability issues you are having. I was having an intermittent issue with mine. I cleaned this and checked that. I added an extra ground to the maf. I found that somehow the maf would drop the ground from time to time. I was having a stumble. It wouldn't idle well at times. Link to comment Share on other sites More sharing options...
morpheus Posted September 29, 2013 Share Posted September 29, 2013 Could it be as simple as the plug on the harness isn't locking onto the injector properly? Link to comment Share on other sites More sharing options...
Superkirby Posted September 29, 2013 Author Share Posted September 29, 2013 Could it be as simple as the plug on the harness isn't locking onto the injector properly? That's what I was thinking so changed the connector. Still nothing. After playing with wires - literally, I was trying to trace the yellow wire off the inector back to the plug and essentially ended up moving them around a little - it worked great for the last few days. Finally last night I noticed driving home from work there was a hint of a stumble creeping back in on occasion. If it follows suit like it has in the past, it should be an on and off problem today and pretty much a constant issue after that. The new harness should be here tomorrow or Tuesday and then will get it changed out and see if that helps. Link to comment Share on other sites More sharing options...
Guest Mrs.Azzo Posted September 30, 2013 Share Posted September 30, 2013 Did you check continuity from the PCM to the injector? If so and it shows good continuity you need to do a voltage drop on the wires in question. You need a factory wiring diagram to start off with. Next disconnect the suspect connector/circuit, in your case the injector. Disconnect the harness from the computer. I like to use a conventional test light but a rigged up automotive light bulb works great. Now you need a some current to run though the wire. I prefer a 12v car battery, but a 9v battery like from an old garage door opener works just as well. You need to connect the battery to the circuit with the test light in series. **Make sure you are on the correct wires and the component and ECU are unplugged or you could introduce voltage to where it's not suppose to go!** If the bulb or light is dim then you know there is an issue in the specific wire either corrosion, or pinched wire that will give you good continuity but cause a voltage drop and not let enough current flow through the wire. You can also use a DVOM if you want to get super technical (Youtube Voltage Drop, there's some great videos). Hope this helps. This technique has saved me countless hours of guessing by isolating a bad wire. Nice looking truck! Link to comment Share on other sites More sharing options...
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